1. Field of the Invention
The present invention relates to a battery and more particularly to an improvement in a collector for connecting a collector connected to at least one of positive and negative plates and a sealing member.
2. Description of the Related Art
In general, an alkali storage battery such as a nickel-hydride storage battery or a nickel-cadmium storage battery has such a structure that a separator is provided between a positive electrode and a negative electrode and they are wound spirally or laminated, and a collecting lead is then connected to the end of the positive electrode or the negative electrode to form an electrode member, the electrode member is accommodated in a metallic battery case to be an outer casing to weld a collector to a sealing member, and the sealing member is then attached to the opening of the battery case with an insulating gasket provided inbetween and is thus closed tightly.
For example, in FIGS. 5 and 6 showing a square nickel-hydride storage battery, a conductive tab 102 for a positive electrode is protruded from the upper part of an electrode member 101 formed by winding a positive plate and a negative plate through a separator, and a plurality of conductive tabs 102 for a positive electrode are converged and are spot welded to one of the ends of a positive electrode collecting lead 103 and the other end is spot welded to an L-shaped positive electrode collector 108, and a positive electrode cap 106 constituting a positive electrode terminal is provided by tightly sealing the opening of an outer casing 109 through a cover member 105 and a gasket 107 to form a sealing member 104.
In this structure, the positive electrode collector 108 is L-shaped and is constituted by a body section 108a attached along the opening and a connecting piece 108b extended vertically from one of the ends of the body section 108a. The connecting piece 108b is extended vertically from the body section 108a to cause a welded electrode to easily abut thereon when the other end of the collecting lead 103 is to be spot welded. Thus, an assembling property can be enhanced.
However, a space is provided between the sealing cap 106 of a battery and the electrode member 101 and the structure can be obtained also in such a state that the component of a sealing member welded section is extended downward. In order to promote an increase in a capacity, it is necessary to maximize the occupation area of the electrode member 101. For this purpose, however, the space provided above the electrode member 101 is reduced. In the conventional structure, therefore, the increase in a capacity is limited.
In the conventional structure, moreover, the connecting piece 108b of the positive electrode collector 108 is extended vertically. A shown in FIG. 5, therefore, there is a problem in that a space between the tip of the connecting piece 108b and the upper end of the electrode member 101 is small and the positive electrode collecting lead 103 comes in contact with the electrode member 101, thereby causing a short-circuit failure.